Field of the Invention
The present invention relates generally to engines, and more specifically to bi-fuel systems that operate using more than one fuel source. For instance, the present system uses both distillate fuel as well as gaseous fuel for engine operation. The present invention also relates generally to refrigerated storage containers.
Description of the Related Art
Engines have been used to generate electrical energy required to drive many large devices. Industrial engines, in particular, are frequently used for large scale operations but suffer from inefficiency due to the large output required. This inefficiency translates into high operational costs.
Recent efforts have been made to make more efficient engines, such as for vehicles including passenger cars and trucks. For instance, multi-fuel engines are available that are capable of running off of different types of fuel, such as gasoline or diesel and an alternate fuel source, such as hydrogen or natural gas. The fuels are stored in separate tanks, and the engine operates off of only one at a time, switching back and forth between fuel sources either manually or automatically. The alternative fuel is used as a fuel supplement rather than entirely replacing gasoline or diesel, and may assist in making such engines more efficient or more environmentally friendly. However, they are not often used.
Refrigerated storage containers, or “reefers” as they are commonly referred to in the industry, are used to both store and transport temperature-sensitive goods that may spoil, degrade, or reduce in usefulness at temperatures higher than ambient or room temperature. The degree of temperature reduction required to maintain or preserve these goods is dependent on the physical and/or chemical characteristics of the particular goods themselves, and may vary from one type to another, requiring as low as zero or sub-zero temperatures. Accordingly, reefer units must be able to accommodate various temperature targets.
It requires a great deal of energy to refrigerate a storage unit, depending on the size of the interior space and the target temperature. Accordingly, a refrigeration unit, often including a compressor or other similar structure to cool the air, is typically driven by an industrial diesel engine, generator, or other power source. These industrial machines, however, are not very cost or energy efficient and their use drives up operation cost. This is frequently exacerbated in the case of mobile reefer units, to which the cost of fuel for transportation must also be factored. It would therefore be beneficial to have a more efficient way to cool refrigerated storage containers, such as reefer units, be they stationary or mobile.